import java.io.*; import java.util.*; import java.text.*; import java.math.*; import java.util.regex.*; public class Solution { public static void main(String[] args) { Scanner in = new Scanner(System.in); int n = in.nextInt(); boolean vertical = true; boolean horizontal = true; int x = in.nextInt(); int y = in.nextInt(); for(int a0 = 1; a0 < n && (horizontal || vertical); a0++){ int xNew = in.nextInt(); if (xNew != x) { horizontal = false; } int yNew = in.nextInt(); if (yNew != y) { vertical = false; } } if (horizontal || vertical) { System.out.println("YES"); } else { System.out.println("NO"); } } }